1. Field of the Invention
The present invention relates to the field of switches for electrical circuits. In particular the present invention relates to an electrical switch which is capable of closing an electrical circuit only when the switch itself is subject to the effects of deceleration.
2. Description of the Prior Art
A variety of impact switches designed for use in conjunction with ordnance devices are known in the prior art. Such switches are designed to react to the effects of deceleration when the ordnance device which carries the switch impacts a particular target. The effect of deceleration upon the switch when the ordnance device impacts results in action within the switch which causes it to close the circuit in which it is located. The ordnance device thus becomes fuzed or armed and explosive actions follow. Typical of prior art impact switches are those known as spring mass devices, piezoelectric sensors, and crush sensors. Each of these types of devices for detecting impact and either completing the circuit or sending a signal for use in fuzing the ordnance device can be found in a variety of different configurations. Spring mass devices in the prior art are all found to be susceptible to bullet impact. None of these devices offer variable sensitivity. The piezoelectric sensors are also susceptible to bullet impact and like the spring mass devices do not offer variable sensitivity. Crush sensors again do not offer variable sensitivity regardless of their configurations in the prior art. What is needed is a simple, reliable device for sensing the impact of an ordnance item with its target and which is insensitive to bullet or other shrapnel impact during the course of the flight of the ordnance device and which offers variable sensitivity. That is what is desired is a device the sensitivity of which can be adjusted in some way so that the time between the time of impact and the time of sending out either a signal or closing a circuit for ordnance device fuzing can be adjusted either by virtue of the inherent design of the device, that is, device selection or by means of a variable element that permits external adjustment prior to use. The need for variable sensitivity of the sensor or switch to the impact is a result of the necessity for permitting the ordnance device to impact the target and in fact penetrate it prior to the ordnance device being fuzed and exploded. Thus, the impact sensor or switch most desirably should have some means of controlling its reaction time.